Re: [PATCH] softirq,tracing: enable to trace softirq raise latency

From: Ingo Molnar
Date: Thu Dec 10 2009 - 03:06:26 EST



* Lai Jiangshan <laijs@xxxxxxxxxxxxxx> wrote:

> Rebase it for the newly codes
> Collect Acks(Acked-by Mathieu Desnoyers and Frederic Weisbecker)
>
>
> From: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
>
> Add a tracepoint for tracing when softirq action is raised.
>
> It and the existed tracepoints complete softirq's tracepoints:
> softirq_raise, softirq_entry and softirq_exit.
>
> And when this tracepoint is used in combination with
> the softirq_entry tracepoint we can determine
> the softirq raise latency.
>
> Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
> Acked-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>

ok, it would be nice to expose this functionality via some sort of 'perf
trace --irqlatency' (or perhaps a separate 'perf irq record' 'perf irq
trace' tool) so that users/developers can make use of this new event and
that we can check that it works and latencies are correct, etc.

Ingo
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